tools/perf/arch/x86/util/perf_regs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <errno.h>
   3 #include <string.h>
   4 #include <regex.h>
   5
   6 #include "../../perf.h"
   7 #include "../../util/util.h"
   8 #include "../../util/perf_regs.h"
   9 #include "../../util/debug.h"
  10
  11 const struct sample_reg sample_reg_masks[] = {
  12         SMPL_REG(AX, PERF_REG_X86_AX),
  13         SMPL_REG(BX, PERF_REG_X86_BX),
  14         SMPL_REG(CX, PERF_REG_X86_CX),
  15         SMPL_REG(DX, PERF_REG_X86_DX),
  16         SMPL_REG(SI, PERF_REG_X86_SI),
  17         SMPL_REG(DI, PERF_REG_X86_DI),
  18         SMPL_REG(BP, PERF_REG_X86_BP),
  19         SMPL_REG(SP, PERF_REG_X86_SP),
  20         SMPL_REG(IP, PERF_REG_X86_IP),
  21         SMPL_REG(FLAGS, PERF_REG_X86_FLAGS),
  22         SMPL_REG(CS, PERF_REG_X86_CS),
  23         SMPL_REG(SS, PERF_REG_X86_SS),
  24 #ifdef HAVE_ARCH_X86_64_SUPPORT
  25         SMPL_REG(R8, PERF_REG_X86_R8),
  26         SMPL_REG(R9, PERF_REG_X86_R9),
  27         SMPL_REG(R10, PERF_REG_X86_R10),
  28         SMPL_REG(R11, PERF_REG_X86_R11),
  29         SMPL_REG(R12, PERF_REG_X86_R12),
  30         SMPL_REG(R13, PERF_REG_X86_R13),
  31         SMPL_REG(R14, PERF_REG_X86_R14),
  32         SMPL_REG(R15, PERF_REG_X86_R15),
  33 #endif
  34         SMPL_REG_END
  35 };
  36
  37 struct sdt_name_reg {
  38         const char *sdt_name;
  39         const char *uprobe_name;
  40 };
  41 #define SDT_NAME_REG(n, m) {.sdt_name = "%" #n, .uprobe_name = "%" #m}
  42 #define SDT_NAME_REG_END {.sdt_name = NULL, .uprobe_name = NULL}
  43
  44 static const struct sdt_name_reg sdt_reg_tbl[] = {
  45         SDT_NAME_REG(eax, ax),
  46         SDT_NAME_REG(rax, ax),
  47         SDT_NAME_REG(al,  ax),
  48         SDT_NAME_REG(ah,  ax),
  49         SDT_NAME_REG(ebx, bx),
  50         SDT_NAME_REG(rbx, bx),
  51         SDT_NAME_REG(bl,  bx),
  52         SDT_NAME_REG(bh,  bx),
  53         SDT_NAME_REG(ecx, cx),
  54         SDT_NAME_REG(rcx, cx),
  55         SDT_NAME_REG(cl,  cx),
  56         SDT_NAME_REG(ch,  cx),
  57         SDT_NAME_REG(edx, dx),
  58         SDT_NAME_REG(rdx, dx),
  59         SDT_NAME_REG(dl,  dx),
  60         SDT_NAME_REG(dh,  dx),
  61         SDT_NAME_REG(esi, si),
  62         SDT_NAME_REG(rsi, si),
  63         SDT_NAME_REG(sil, si),
  64         SDT_NAME_REG(edi, di),
  65         SDT_NAME_REG(rdi, di),
  66         SDT_NAME_REG(dil, di),
  67         SDT_NAME_REG(ebp, bp),
  68         SDT_NAME_REG(rbp, bp),
  69         SDT_NAME_REG(bpl, bp),
  70         SDT_NAME_REG(rsp, sp),
  71         SDT_NAME_REG(esp, sp),
  72         SDT_NAME_REG(spl, sp),
  73
  74         /* rNN registers */
  75         SDT_NAME_REG(r8b,  r8),
  76         SDT_NAME_REG(r8w,  r8),
  77         SDT_NAME_REG(r8d,  r8),
  78         SDT_NAME_REG(r9b,  r9),
  79         SDT_NAME_REG(r9w,  r9),
  80         SDT_NAME_REG(r9d,  r9),
  81         SDT_NAME_REG(r10b, r10),
  82         SDT_NAME_REG(r10w, r10),
  83         SDT_NAME_REG(r10d, r10),
  84         SDT_NAME_REG(r11b, r11),
  85         SDT_NAME_REG(r11w, r11),
  86         SDT_NAME_REG(r11d, r11),
  87         SDT_NAME_REG(r12b, r12),
  88         SDT_NAME_REG(r12w, r12),
  89         SDT_NAME_REG(r12d, r12),
  90         SDT_NAME_REG(r13b, r13),
  91         SDT_NAME_REG(r13w, r13),
  92         SDT_NAME_REG(r13d, r13),
  93         SDT_NAME_REG(r14b, r14),
  94         SDT_NAME_REG(r14w, r14),
  95         SDT_NAME_REG(r14d, r14),
  96         SDT_NAME_REG(r15b, r15),
  97         SDT_NAME_REG(r15w, r15),
  98         SDT_NAME_REG(r15d, r15),
  99         SDT_NAME_REG_END,
 100 };
 101
 102 /*
 103  * Perf only supports OP which is in  +/-NUM(REG)  form.
 104  * Here plus-minus sign, NUM and parenthesis are optional,
 105  * only REG is mandatory.
 106  *
 107  * SDT events also supports indirect addressing mode with a
 108  * symbol as offset, scaled mode and constants in OP. But
 109  * perf does not support them yet. Below are few examples.
 110  *
 111  * OP with scaled mode:
 112  *     (%rax,%rsi,8)
 113  *     10(%ras,%rsi,8)
 114  *
 115  * OP with indirect addressing mode:
 116  *     check_action(%rip)
 117  *     mp_+52(%rip)
 118  *     44+mp_(%rip)
 119  *
 120  * OP with constant values:
 121  *     $0
 122  *     $123
 123  *     $-1
 124  */
 125 #define SDT_OP_REGEX  "^([+\\-]?)([0-9]*)(\\(?)(%[a-z][a-z0-9]+)(\\)?)$"
 126
 127 static regex_t sdt_op_regex;
 128
 129 static int sdt_init_op_regex(void)
 130 {
 131         static int initialized;
 132         int ret = 0;
 133
 134         if (initialized)
 135                 return 0;
 136
 137         ret = regcomp(&sdt_op_regex, SDT_OP_REGEX, REG_EXTENDED);
 138         if (ret < 0) {
 139                 pr_debug4("Regex compilation error.\n");
 140                 return ret;
 141         }
 142
 143         initialized = 1;
 144         return 0;
 145 }
 146
 147 /*
 148  * Max x86 register name length is 5(ex: %r15d). So, 6th char
 149  * should always contain NULL. This helps to find register name
 150  * length using strlen, insted of maintaing one more variable.
 151  */
 152 #define SDT_REG_NAME_SIZE  6
 153
 154 /*
 155  * The uprobe parser does not support all gas register names;
 156  * so, we have to replace them (ex. for x86_64: %rax -> %ax).
 157  * Note: If register does not require renaming, just copy
 158  * paste as it is, but don't leave it empty.
 159  */
 160 static void sdt_rename_register(char *sdt_reg, int sdt_len, char *uprobe_reg)
 161 {
 162         int i = 0;
 163
 164         for (i = 0; sdt_reg_tbl[i].sdt_name != NULL; i++) {
 165                 if (!strncmp(sdt_reg_tbl[i].sdt_name, sdt_reg, sdt_len)) {
 166                         strcpy(uprobe_reg, sdt_reg_tbl[i].uprobe_name);
 167                         return;
 168                 }
 169         }
 170
 171         strncpy(uprobe_reg, sdt_reg, sdt_len);
 172 }
 173
 174 int arch_sdt_arg_parse_op(char *old_op, char **new_op)
 175 {
 176         char new_reg[SDT_REG_NAME_SIZE] = {0};
 177         int new_len = 0, ret;
 178         /*
 179          * rm[0]:  +/-NUM(REG)
 180          * rm[1]:  +/-
 181          * rm[2]:  NUM
 182          * rm[3]:  (
 183          * rm[4]:  REG
 184          * rm[5]:  )
 185          */
 186         regmatch_t rm[6];
 187         /*
 188          * Max prefix length is 2 as it may contains sign(+/-)
 189          * and displacement 0 (Both sign and displacement 0 are
 190          * optional so it may be empty). Use one more character
 191          * to hold last NULL so that strlen can be used to find
 192          * prefix length, instead of maintaing one more variable.
 193          */
 194         char prefix[3] = {0};
 195
 196         ret = sdt_init_op_regex();
 197         if (ret < 0)
 198                 return ret;
 199
 200         /*
 201          * If unsupported OR does not match with regex OR
 202          * register name too long, skip it.
 203          */
 204         if (strchr(old_op, ',') || strchr(old_op, '$') ||
 205             regexec(&sdt_op_regex, old_op, 6, rm, 0)   ||
 206             rm[4].rm_eo - rm[4].rm_so > SDT_REG_NAME_SIZE) {
 207                 pr_debug4("Skipping unsupported SDT argument: %s\n", old_op);
 208                 return SDT_ARG_SKIP;
 209         }
 210
 211         /*
 212          * Prepare prefix.
 213          * If SDT OP has parenthesis but does not provide
 214          * displacement, add 0 for displacement.
 215          *     SDT         Uprobe     Prefix
 216          *     -----------------------------
 217          *     +24(%rdi)   +24(%di)   +
 218          *     24(%rdi)    +24(%di)   +
 219          *     %rdi        %di
 220          *     (%rdi)      +0(%di)    +0
 221          *     -80(%rbx)   -80(%bx)   -
 222          */
 223         if (rm[3].rm_so != rm[3].rm_eo) {
 224                 if (rm[1].rm_so != rm[1].rm_eo)
 225                         prefix[0] = *(old_op + rm[1].rm_so);
 226                 else if (rm[2].rm_so != rm[2].rm_eo)
 227                         prefix[0] = '+';
 228                 else
 229                         strncpy(prefix, "+0", 2);
 230         }
 231
 232         /* Rename register */
 233         sdt_rename_register(old_op + rm[4].rm_so, rm[4].rm_eo - rm[4].rm_so,
 234                             new_reg);
 235
 236         /* Prepare final OP which should be valid for uprobe_events */
 237         new_len = strlen(prefix)              +
 238                   (rm[2].rm_eo - rm[2].rm_so) +
 239                   (rm[3].rm_eo - rm[3].rm_so) +
 240                   strlen(new_reg)             +
 241                   (rm[5].rm_eo - rm[5].rm_so) +
 242                   1;                                    /* NULL */
 243
 244         *new_op = zalloc(new_len);
 245         if (!*new_op)
 246                 return -ENOMEM;
 247
 248         scnprintf(*new_op, new_len, "%.*s%.*s%.*s%.*s%.*s",
 249                   strlen(prefix), prefix,
 250                   (int)(rm[2].rm_eo - rm[2].rm_so), old_op + rm[2].rm_so,
 251                   (int)(rm[3].rm_eo - rm[3].rm_so), old_op + rm[3].rm_so,
 252                   strlen(new_reg), new_reg,
 253                   (int)(rm[5].rm_eo - rm[5].rm_so), old_op + rm[5].rm_so);
 254
 255         return SDT_ARG_VALID;
 256 }